Engines, including diesel engines, gasoline engines, natural gas engines, and other engines known in the art, may exhaust a complex mixture of air pollutants. The air pollutants may be composed of both gaseous constituents, such as NOx, as well as solid material, such as particulate matter. Particulate matter may include ash and unburned carbon particles and is sometimes referred to as soot.
The amount of particulate matter and gaseous pollutants emitted from an engine may be regulated depending on the type, size, and/or class of engine. Due to increased environmental concerns, exhaust emission standards have become more stringent. In order to meet these emissions standards, engine manufacturers have pursued improvements in several different engine technologies, such as fuel injection, engine management, and air induction. In addition, engine manufacturers have developed devices and systems for treatment of engine exhaust after it leaves the engine. Such systems are often referred to as “after-treatment” systems. After-treatment systems may include after-treatment components, such as catalytic converters and particulate traps.
In order to update older and/or less advanced machines, exhaust after-treatment systems are often retrofitted. As after-treatment systems become more complex, retrofitting such systems is also becoming correspondingly difficult. Many after-treatment systems include multiple treatment components (e.g., catalyst, particulate trap, etc.). Some systems may include selective catalytic reduction (SCR) catalysts that utilize a reductant for reducing the amount of NOx in exhaust. A typical SCR reductant is ammonia, usually delivered in the form of urea. Such systems may include a urea storage tank, a pump, metering equipment, and associated plumbing for delivering urea to the catalysts to support the reduction reaction. In addition, exhaust after-treatment systems may also include sensors for measuring temperature, pressure, flowrates, etc. and a controller to operate the system.
Thus, after-treatment systems include complex electronics, wiring, plumbing, sensors, and physical components. Because of this complexity, installation of an after-treatment system can require a significant amount of labor, and may necessitate multiple tradesmen to install a single system. In some cases, the cost of installation rivals that of the system itself. Accordingly, it is desirable to provide an after-treatment system for which installation (be it retrofitting or initial manufacturing) is significantly simplified.
At least one system has been developed that attempts to simplify portions of an after-treatment system by consolidating components thereof. U.S. Pat. No. 6,192,676 (the '676 patent) discloses a system including a urea storage container and a control unit associated therewith. The '676 patent discloses that the control unit may be mounted on the urea storage container. The '676 patent, however, does not disclose any consolidation of other after-treatment components. Urea storage containers only represent a small portion of an after-treatment system. Further, in stationary applications (e.g., electric power generation sets), urea storage containers are often remote from the engine and, therefore, may not be a particularly problematic and/or labor-intensive part of the installation process. There remains a need for a simplified after-treatment system configured for a streamlined installation process.
The present disclosure is directed to improvements in existing after-treatment systems.